Although Keiley was a Wall Street lawyer, his photographic activities were various and influential. In addition to writing art criticism and experimenting with various photographic processes, he collaborated with Alfred Stieglitz on the invention of the glycerine process, which permitted the partial development of platinum prints to facilitate obtaining the soft-focus tones they favored.
Keiley was an editor of both Camera Notes and Camera Work—so admired by his colleagues that his name remained on the masterhead of Camera Work even after his death. One of the founding members of the Photo-Secession, Keiley sought to align great photographers with great painters and other artists.
The beautiful wife of the prominent modernist painter Arthur Carles, Mercedes de Cordoba [SAAM, 1994.91.99] was photographed by Keiley on several occasions.
Merry A. Foresta American Photographs: The First Century (Washington, D.C.: National Museum of American Art with the Smithsonian Institution Press, 1996)